1. Technical Field
The inventive arrangements relate generally to methods and apparatus for providing advanced operating features for recording data to recordable DVD media, and more particularly to a method and apparatus for DVD-ROM backwards-compatible defective sector management in recordable DVD media.
2. Description of the Related Art
Various devices have been developed to enable consumers to record video and/or audio programs for later presentation. Such devices include tape recorders, video cassette recorders, recordable compact disks, and most recently, recordable digital versatile disks (DVD). Hard drives and magneto optical disks have also been used. A DVD in which data can be recorded once only, and thereafter is essentially a DVD read only memory, is referred to by the acronym DVD-R. The acronym DVD-R also has been used generally to refer to write-once, or record-once, technology.
In contrast to DVD-R, several formats exist in which data can be recorded to a DVD, erased and re-recorded. In sum, such a DVD can be overwritten or rewritten. These DVDs typically are referred to by the acronyms DVD-RAM, DVD-RW and DVD+RW. Although, as of this time no uniform industry standard has been adopted, the acronyms DVD-RAM, DVD-RW and DVD+RW have been used generally to refer to the respective re-writable DVD technologies. Still, reference herein to re-writable DVD technology, devices and methods and recordable DVD media is generally intended to encompass all of the standards which are now being used, as well as those which may be developed in the future.
Present DVDs can have a logical file structure in which audio-video content can be stored. Specifically, as shown in FIG. 7, at the top of the file structure hierarchy of a DVD 700, one or more titles 701 can exist which can loosely correlate to program episode titles. Titles 701 can consist of control data 702 in addition to one or more Video Object Sets 703 (VOBS). The control data 702 can contain information for managing the title 701. Each VOBS 703 can include a plurality of Video Objects (VOB) 704. Each VOB 704 preferably includes a plurality of Cells 705. Each Cell 705 preferably includes a plurality of Video Object Units (VOBU) 706. Each VOBU 706 roughly correlates to a group of pictures which is the smallest addressable chunk in the DVD 700.
Notably, each VOBU 706 can contain an integer number of video frames. As such, each VOBU 706 can contain 0.4 to 1.0 seconds of presentation material. A typical VOBU 706 in a commercial motion picture can contain 0.5 second of presentation material. Notably, each VOBU 706 can include a sequence of packs 707 positioned in recording order. Preferably, each VOBU can begin with a navigation pack 708 (NV_PCK or NAV_PACK) which can be followed by audio-visual data packs 709, for example video packs (V_PCK), audio packs (A_PCK) and sub-picture packs (SP_PCK). The NV-PCK 708 can contain navigation information, which can be useful in implementing trick modes of operation. The NV_PCK 708 also can include presentation control information (PCI) and data search information (DSI).
Recordable DVD media can be used for thousands or even tens of thousands of times for recordings. For each recording, defective sectors in the recordable DVD media potentially can arise. As a result, recordable DVD media can accumulate a substantial number of defective sectors during the operational lifetime of the recordable DVD media. Yet, defective sectors in recordable DVD media can inhibit proper playback of data stored in the recordable DVD media. Specifically, defective sectors in the control data area can invalidate the control data. Moreover, defective sectors in video data in a VOBU can cause video freeze or blockiness. Additionally, defective sectors in audio data in a VOBU can cause audio distortion or noise. Finally, defective sectors in a menu area can damage a menu.
In traditional recordable media, for example hard disk drives, generally there exists two methods for managing defective sectors. A first method has been referred to as the “sector slipping method”. In the sector slipping method, when a defect is detected in one of the consecutive data sectors, the sector immediately following the defective sector is configured to become the logical next adjacent sector to the valid sector immediately preceding the defective sector. This configuration can be implemented by setting aside the defective sector and mapping the following sector to become the sector logically adjacent to the valid sector. A second method includes the re-allocation of a reserved sector in substitution for the defective sector. Specifically, when a defective sector is detected on one of the tracks of some recordable DVD media, a reserve sector on one of the tracks is re-allocated in substitution for the defective sector.
Notwithstanding traditional methods for defect management, with regard to recordable DVD media, a chosen defect management method must account for existing DVD-ROM technology. Specifically, in recordable DVD media such as DVD-RW, DVD-RAM, DVD+RW and others, a chosen defect management method must not inhibit the requirement that data written to the recordable DVD media remain readable, (e.g. backwards compatible) by current DVD-ROM players. Notwithstanding, currently DVD-ROM players do not have a mechanism for handling defective sectors. Moreover, the DVD-ROM specification requires that data must be continuous on a recordable DVD disk. Nevertheless, the management of defective sectors in recordable DVD media using traditional methods for defect management can cause the data stored in the recordable DVD media to become discontinuous.